The book provides information essential for anyone interested in the ecology of the American Southwest, including land managers, environmental planners, conservationists, ecologists and students. It is unique in its coverage of the hows and whys of dynamics (changes) in the major types of vegetation occurring on southwestern mountains and plateaus. It explains the drivers and processes of change, describes historical changes and provides conceptual models that diagrammatically illustrate past, present, and potential future changes. All major types of vegetation are covered: spruce-fir, mixed conifer, and ponderosa pine forests, pinyon-juniper vegetation, subalpine-montane grassland, and Gambel oak and interior chaparral shrublands. The focus is on vegetation that is relatively undisturbed, i.e., in natural and near-natural condition, and how it responds to natural disturbances such as fire and drought, as well as to anthropogenic disturbances such as fire exclusion and invasive species

The objective of the National Park Service (NPS) Vegetation Inventory is to classify vegetation as ecological community types in each of more than 250 NPS Inventory and Monitoring park units ("parks") in the United States outside of Alaska and to map vegetation to that classification scheme developed for the unit. This guidance is a revision and update of the 1994 guidance on vegetation classification within the NPS Vegetation Inventory (The Nature Conservancy and Environmental Systems Research Institute 1994) and supersedes the 1994 version.